<template>
  <div>
    <h1>子1 {{ n }}</h1>
    <button @click="fn">传递子2</button>
  </div>
</template>

<script>
export default {
  data() {
    return {
      n: 777,
    };
  },
  methods: {
    fn() {
      this.$emit("onezhi", this.n);
    },
  },
};
</script>

<style lang="scss" scoped>
</style>